Cyclone type dirt separator and electric vacuum cleaner

ABSTRACT

A cyclone type dirt separator disposed at an intermediate point of an suction tube which connects the suction fitting and the cleaner main body of an electric vacuum cleaner, the dirt separator including: a dirt separating section which causes the suction air to undergo a spiral flow and conducts air from the vicinity of the center of this spiral flow to the cleaner main body, a dirt collection chamber which is attached to the dirt separating section from below and causes the dirt separated from the spiral flow to drop so that the dirt is collected inside the dirt collection chamber, and a recessed portion which is formed in the vicinity of the inside bottom center of the dirt collection chamber so as to be recessed downward.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a cyclone type dirt separator which is provided at an intermediate point of the suction tube of an electric vacuum cleaner and further relates to an electric vacuum cleaner that uses such a separator.

2. Description of the Related Art

In typical electric vacuum cleaners, suction air that involves dirt that is sucked in via a suction fitting (suction nozzle) is led to the cleaner main body via a suction tube. Here, the suction air that contains dirt passes through a filter installed in the cleaner main body, and dirt is collected by this filter.

In collection of the dirt, if relatively large pieces of dirt such as paper debris, sludge and the like are contained in large quantities in the dirt that is sucked in, the filter quickly becomes clogged, so that the suction capacity soon drops. Accordingly, the filter must be cleaned frequently, and this frequent filter cleaning is in fact a problem of poor efficiency. In order to solve this problem, a system has been proposed in which a cyclone type dirt separator is interposed at an intermediate point of the suction tube that connects the suction fitting and the cleaner main body, so that the cyclone type dirt separator captures and removes relatively large pieces of dirt.

In the cyclone type dirt separator disclosed in Japanese Patent No. 3102864, the lower end of an exhaust tube that sucks air from the vicinity of a spiral flow into the cleaner main body is closed, numerous fine through-holes are formed in the outer circumferential surface of this tube, and air is sucked from these fine through-holes and discharged into the cleaner main body. In this structure, the dirt that is separated from the spiral flow is collected in a contaminant collection trough (a dirt collection part) that extends downward and surrounds the exhaust tube.

On the other hand, in the cyclone type dirt separators of Japanese Patent Application Laid-Open (Kokai) Nos. 2003-135336 and H10-85159, the open lower end of an exhaust tube is caused to face the vicinity of the center of the dust separating section that generates a spiral flow, and the lower part of the dust separating section is communicated with a dust collecting part that is provided below the dust separating section via a dust collecting opening that is in the form of a funnel. In this structure, the dirt that is separated by the spiral flow in the dust separating section drops into the dust collecting part via the dust collecting opening.

However, in the system of Japanese Patent No. 3102864, dirt separated by centrifugal force in the spiral flow is conducted downward along the inside circumferential wall of the contaminant collecting trough; accordingly, the separation of dirt and air can be accomplished with good efficiency. However, since the fluid motion of the spiral flow enters the interior of the contaminant collecting trough along the inside circumferential wall of the contaminant collecting trough, the air inside the contaminant collecting trough undergoes a spiral flow. As a result, the dirt that collects in the bottom of the contaminant collecting trough is entrained by the fluid motion (spiral flow) of this air and may be discharged from the exhaust tube. This dirt causes clogging of the filter of the cleaner main body.

In the systems of Japanese Patent Application Laid-Open (Kokai) Nos. 2003-135336 and H10-85159, a spiral flow is generated in the dust separating section, and dirt is collected in the dust collecting part separated by the dust collecting opening installed in the funnel-form bottom. Consequently, the spiral flow inside the dust separating section tends not to enter the dust collecting part. Accordingly, it would appear that the amount of dirt that is entrained by the spiral flow in dust collecting part is small compared to that seen in the system of Japanese Patent No. 3102864.

However, a spiral flow would be generated inside the dust collecting part according to the amount of suction air, so that dirt may be entrained; and secure prevention of the entrainment of dirt in the dust collecting part is difficult. Furthermore, since the dust collecting part is installed separately from the dust separating section, the total length of the structure increases, causing a problem of increased size of the apparatus.

BRIEF SUMMARY OF THE INVENTION

Accordingly, the first object of the present invention is to provide a cyclone type dirt separator which assuredly prevents the entrainment of dirt accumulated in the contaminant collecting trough or dust collecting part by spiral flow of air, thus preventing the exhaust of entrained dirt and intake of such dirt into the cleaner main body.

The second object of the present invention is to provide an electric vacuum cleaner that is equipped with such a cyclone type dirt separator.

The above object is accomplished by a unique structure of the present invention for a cyclone type dirt separator, which is interposed at an intermediate point of the suction tube connecting the suction fitting and a cleaner main body of an electric vacuum cleaner, and which separates dirt from the suction air containing dirt that is sucked in from the suction fitting; and in the present invention, the separator is comprised of:

-   -   a dirt separating section which causes the suction air to make a         spiral flow and conducts air from the vicinity of the center of         this spiral flow to the cleaner main body,     -   a dirt collection chamber which is mounted on this dirt         separating section from below and causes the dirt separated from         the spiral flow to drop so that the dirt is collected in said         dirt collection chamber, and     -   a recessed portion formed in the vicinity of the inside bottom         center of the dirt collection chamber so as to be recessed         downward.

In this structure of the present invention, since the recessed portion is formed in the vicinity of the center of the inside bottom of the dirt collection chamber, the dirt that enters the dirt collection chamber is conducted into the inside bottom surface and is collected in the recessed portion. In addition, even if a spiral flow is generated in the dirt collection chamber, since this spiral flow tends not to enter the sunken recessed portion, no entrainment of the dirt accumulated in the recessed portion occurs, and dirt in the vicinity of the inside bottom likewise tends not to become entangled and entrained with the dirt accumulated in this recessed portion. Accordingly, dirt that has once entered the dirt collection chamber is prevented from being discharged from the exhaust tube, so that the need for frequent cleaning of the filter inside the cleaner main body is eliminated.

The above object is further accomplished by a unique structure of the present invention for an electric vacuum cleaner that comprises:

a cleaner main body provided with an electrically driven air blower;

a suction tube with one end thereof connected to the vacuum suction port of this cleaner main body;

a suction fitting which is attached to the tip end of this suction tube; and

a cyclone type dirt separator which is interposed at an intermediate point of the suction tube, the cyclone type dirt separator causing suction air containing dirt that is sucked in from the suction fitting to undergo a spiral flow, separating dirt from this air in spiral flow, and causing the separated dirt that is thus separated to drop into a substantially tubular dirt collection chamber so that this dirt is collected in the dirt collection chamber; and in addition,

the dirt collection chamber of the cyclone type dirt separator has a recessed portion that is formed in the vicinity of the inside bottom center of the dirt collection chamber so that it is recessed downward.

Accordingly, in the electric vacuum cleaner of the present invention, dirt that has once entered the dirt collection chamber of the cyclone type dirt separator is prevented from being discharged from the exhaust tube, and the need for frequent cleaning of the filter inside the cleaner main body is eliminated.

In the cyclone type dirt separator of the present invention, the separating section may comprise an exhaust tube, which is disposed substantially in coaxial with the central axis of the spiral of the spiral flow, whose lower end is closed off, and which exhausts air via the exhaust openings in the circumferential surface; and the dirt collection chamber may have a substantially tubular shape that extends downward while surrounding this exhaust tube. In this case, the dirt that is separated by the centrifugal force arising from the spiral flow can be conducted into the inside bottom of the dirt collection chamber with good efficiency, so that the dirt separation is done efficiently. Furthermore, one part (the upper part) of the dirt collection chamber surrounds the exhaust tube and forms an integral unit with the separating section, thus generating a spiral current of air; accordingly, this structure contributes the overall size reduction.

Furthermore, with a substantially flange-form baffling plate which narrows the air flow path between this baffling plate and the inside wall of the dirt collection chamber, the entry of the spiral flow into the inside bottom of the dirt collection chamber is prevented, so that the entrainment of dirt accumulated in this inside bottom and the outflow of such dirt together with the exhaust can be much more securely prevented.

In the present invention, the inside surface in the vicinity of the opening of the recessed portion and the inside bottom surface of the dirt collection chamber are not smoothly continuous, or such surfaces meet with a ridge in between. For example, the inside bottom surface of the dirt collection chamber can be formed as a so-called artillery shell-form curved surface in which the diameter is smoothly reduced downward, and this curved surface and the opening circular edge of the recessed portion abuts at an obtuse angle to form a substantially annular edge shape. With this structure, if a spiral flow occurs in the inside bottom, the spiral flow is less likely to enter the recessed portion.

The recessed portion can be of a substantially cylindrical shape with a closed bottom. However, the present invention is not limited to this structure, and a square tubular shape recessed portion that has a closed bottom or the like can be also used. By way of setting the diameter of the opening of the recessed portion at approximately ½ to ⅓ of the diameter near the center of the dirt collection chamber, the intrusion of the spiral flow can be sufficiently cut off while maintaining the capacity (volume) of the recessed portion at a large value.

In the present invention, it is preferable that the cyclone type dirt separator be installed in the connecting portion between a flexible tube and an extension tube that constitute the suction tube of an electric vacuum cleaner; however, this cyclone type dirt separator can be disposed, for instance, in the vicinity of the tip end of the extension tube and in the vicinity of the vicinity of the rear end of the flexible tube (immediately before the cleaner main body or the like).

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 shows the electric vacuum cleaner of the present invention equipped with a cyclone type dirt separator according to one embodiment of the present invention;

FIG. 2 is a sectional side view of the cyclone type dirt separator;

FIG. 3 is a sectional view of the essential portion of the cyclone type dirt separator;

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3;

FIG. 5 is a sectional view taken along the line V-V in FIG. 4; and

FIG. 6 illustrates the exhaust openings of the exhaust tube inside the dirt separator.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1, the reference numeral 10 is a cleaner main body, and this cleaner main body 10 is equipped with a filter 12 and an electrically driven air blower 14. A suction tube 16 connected to the cleaner main body 10 is comprised of a flexible tube 18 and an extension tube 20, and a cyclone type dirt separator 22 is provided at an intermediate point of this suction tube 16. The electrically driven air blower 14 generates a suction force by rotating a fan (not shown) at high speed with an electric motor (not shown).

The electric vacuum cleaner 10 is indeed usable without a cyclone type dirt separator 22; and in this case, the flexible tube 18 (or the forward end of the flexible tube 18) and the extension tube 20 (or the rear end of the extension tube 20) are directly connected to each other to form the suction tube 16. When a cyclone type dirt separator 22 is used, the cyclone type dirt separator 22 is interposed between the flexible tube 18 and the extension tube 20. In other words, the forward end of the flexible tube 18 is connected to the rear end of the dirt separator 22 (or to the exhaust tube 32, which will be described later, of the dirt separator 22), and the rear end of the flexible tube 18 is connected to the cleaner main body 10, and a suction fitting (suction brush) 24 is attached to the forward end of the extension tube 20 and the rear end of the extension tube 20 is connected to the dirt separator 22 (or to the suction intake tube 34, which will be described later, of he dirt separator 22) as shown by arrows in FIG. 1.

When a switch (not shown) on the cyclone type dirt separator 22 is turned on, the electric motor of the air blower is started; and an air suction negative pressure is generated in the suction fitting 24. Air that contains dirt is sucked in via the suction fitting 24, and relatively large pieces of dirt are separated from this suction air by the cyclone type dirt separator 22; and then the air enters the cleaner main body 10. This air passes through the cleaner main body and is exhausted to the outside.

As seen from FIG. 2, the cyclone type dirt separator 22 is comprised of a dirt separating section 26, a dirt collection chamber 28, and a grip section 30.

The dirt separating section 26 includes an exhaust tube 32, a suction intake tube 34, a spiral flow passage 38 and a spiral flow compartment 40. The exhaust tube 32 is, at its end, connected to the flexible tube 18; and this exhaust tube 32 extends downward and is bent at its intermediate point to take a substantially shallow V shape when viewed from the side as seen from FIG. 2. The suction intake tube 34 is disposed parallel to and on a different axis than the lower part of the exhaust tube 32, and the lower end of the suction intake tube 34 is connected to the extension tube 20. The spiral flow passage 38 is provided so as to communicate with the upper end of the suction intake tube 34 and is led to the outer circumference of the exhaust tube 32 so that the suction air is put in a spiral flow 36 (see FIG. 3). The spiral flow compartment 40 separates dirt from the suction air by means of the spiral flow 36 of the air. The exhaust tube 32 is disposed in substantially coaxial with the central axis of the rotation of the spiral flow 36.

As shown in FIG. 5, the spiral flow passage 38 is formed by being surrounded by a partition wall 38 a that constitutes the lower wall of the spiral flow passage 38 which forms a partition with the spiral flow compartment 40, a flow passage opening 38 b that is formed in this partition wall 38 a, an inclined wall 38 c that constitutes the upper wall of the spiral flow passage 38, a circular arc form outer circumferential wall 38 d, and an inner circumferential wall 38 e. The flow passage opening 38 b is formed by cutting away the partition wall 38 a for the length L in the circumferential direction. The inner circumferential wall 38 e is formed by the outer circumferential surface of the exhaust tube 32. The upstream side of the inclined wall 38 c (the upstream side being the part located on the suction intake tube 34 side) is connected to the upper wall of the suction intake tube 34, and the downstream side (which is the portion located on the partition wall 38 a side) is connected to the rear edge 38 f (which is on the downstream side in the spiral direction) of the opening 38 b.

The exhaust tube 32 is formed, on its circumferential wall, with numerous exhaust openings 42 (see FIG. 6) so that the exhaust openings 42 face the spiral flow compartment 40. Each of the exhaust openings 42 is in a slit-form having longer longitudinal sides in the longitudinal direction of the exhaust tube 32 than the width in the circumferential direction. Thus, the exhaust opening 42 is, for instance, approximately 20 mm long and approximately 6 mm wide. These exhaust openings 42 are provided in two (upper and lower) stages in the longitudinal direction of the exhaust tube 32, and they prevent large pieces of debris such as paper scraps or the like from being sucked into the exhaust tube 32. The lower end 32 a of the exhaust tube 32 is closed, and a baffling plate 44 that extends substantially in the form of a cone is disposed on this lower end of the exhaust tube 32. In the shown embodiment, the baffling plate 44 has a substantially circular (reversed) conical shape so that the diameter gradually increases toward its lower edge.

With the structure described above, air or dirty air is sucked in through the suction fitting (suction brush) 24 and rapidly flows through the extension tube 20 and into the suction intake tube 34 of the separator 22. Then, the air enters the spiral flow passage 38, flows along the curved outer and inner circumferential walls 38 d and 38 e and hits the inclined wall 38 c, so that the air, while being rotating, flows downward into the spiral flow compartment 40 through the flow passage opening 38 b, thus forming a spiral flow 36 or “cyclone.” The spiral flow 36, particularly the portion of the air which is in the vicinity of the center of the spiral flow 36, enters the exhaust tube 32 through the exhaust openings 42 of the exhaust tube 32 so that large pieces of dirt in the air are caught by the striped pattern portions between the exhaust openings 42 and thus separated and removed from the spiral flow 36, and the air without large pieces of dirt eventually flows into the cleaner main body 10 through the flexible tube 18.

The dirt collection chamber 28 has a shape of a substantially artillery shell in which the upper end is open and the lower part shows a gradual and smooth decrease in diameter. The dirt collection chamber 28 is, at its upper end, attached to the dirt separating section 26 in a coaxial relation with the exhaust tube 32, and the dirt collection chamber 28 is detachable with reference to the dirt separating section 26.

The spiral flow compartment 40 is provided in coaxial with the exhaust tube 32 between the exhaust tube 32 and the upper part of the dirt collection chamber 28.

The diameter of the baffling plate 44 is set so that air is allowed to flow between the baffling plate 44 and the inside surface of the dirt collection chamber 28, so that the spiral flow 36 is prevented from flowing around beneath the baffling plate 44 and so that a gap that suppresses any back flow of dirt is formed.

The dirt collection chamber 28 is provided so that the inside bottom surface 46 is takes a curved surface that has a smooth decrease in diameter in the downward direction. A recessed portion 48 that sinks downward is formed in the center of this inside bottom surface 46 of the dirt collection chamber 28. The recessed portion 48 is in a shape of a cylinder with a closed bottom, and the diameter of this recessed portion is approximately ½ to ⅓ of the diameter of the dirt collection chamber 28. More specifically, the diameter of this recessed portion 48 is approximately ½ to ⅓ of the diameter of the approximately the vertically central portion of the dirt collection chamber 28 which is substantially at the height of the baffling plate 44. As best seen from FIG. 3, the central axis of the recessed portion 48 is set on the central axis A of the exhaust tube 32, thus being on the axis of the rotation of the spiral flow 36.

The curved surface of the inside bottom surface 46 of the dirt collection chamber 28 and the inside surface in the vicinity of the opening or of the opening edge 48 a of the recessed portion 48 are formed so that they are not smoothly continuous (or unsmoothly continuous). In other word, as best seen from FIG. 3, the portion where the inside bottom surface 46 of the dirt collection chamber 28 and the opening or the opening edge 48 a of the recessed portion 48 abut each other with an obtuse-angle and thus takes an obtuse-angle edge form surface or a step form surface. Since this abutting surface is thus a surface that is bent in a discontinuous form, edge form or step form from the inside bottom surface 46 to the recessed portion 48, even if the spiral flow 36 drops down along the inside bottom surface 46, this spiral flow is blocked by the opening edge 48 a of the recessed portion 48, and dirt that has dropped into the recessed portion 48 is not entrained by the spiral flow. Furthermore, dirt that drops into the dirt collection chamber 28 is prevented from being entrained since such dirt dropping into the dirt collection chamber 28 is entangled with dirt that has previously been dropped in the bottom of the dirt collection chamber 28.

The dirt collection chamber 28 is detachable. In other words, as shown in FIGS. 1 and 2, the hook 50 provided in the vicinity of the lower end of the suction intake tube 34 is provided so that it is engaged with and disengaged from the outside of the recessed portion 48 positioned at the lower end of the dirt collection chamber 28. When the dirt collection chamber 28 is set on the suction intake tube 34 as shown in FIGS. 2 and 3, the dirt collection chamber 28 is fastened in place by this hook 50. When dirt that has accumulated inside the dirt collection chamber 28 is to be discarded, the hook 50 is disengaged from the recessed portion 48, the dirt collection chamber 28 is removed from the suction intake tube 34, and the dirt inside the recessed portion 48 is discharged. 

1. A cyclone type dirt separator, which is provided at an intermediate point of a suction tube that connects a suction fitting and a cleaner main body of an electric vacuum cleaner and which separates dirt from suction air that contains dirt and is sucked in from the suction fitting, said separator comprising: a dirt separating section which causes the suction air to make a spiral flow and conducts air in a spiral flow to said cleaner main body, a dirt collection chamber which is mounted on said dirt separating section from below and causes dirt separated from the spiral flow to drop so that dirt is collected in said dirt collection chamber, and a recessed portion formed in the vicinity of an inside bottom center of said dirt collection chamber so as to be recessed downward.
 2. The cyclone type dirt separator according to claim 1, wherein said dirt separating section includes an exhaust tube which is disposed to be substantially in coaxial with a central axis of spiral of the spiral flow, said exhaust tube exhausting air via exhaust openings formed in a circumferential surface of said exhaust tube, and a lower end of said exhaust tube being closed off; and said dirt collection chamber is in a substantially tubular shape that extends downward and surrounds said exhaust tube.
 3. The cyclone type dirt separator according to claim 2, wherein said exhaust tube is provided at a lower end thereof with a substantially flange-form baffling plate which protrudes toward an inside wall of said dirt collection chamber and suppresses a flow of air in upward and downward directions.
 4. The cyclone type dirt separator according to any one of claims 1 through 3, wherein an inside surface in the vicinity of an opening of said recessed portion and an inside bottom surface of said dirt collection chamber are formed to be unsmoothly continuous to each other.
 5. The cyclone type dirt separator according to claim 4, wherein said inside bottom surface of said dirt collection chamber is formed by a curved surface that shows a gradual decrease in diameter in downward direction, and said curved surface and an opening edge of said recessed portion takes an edge-form obtuse angle.
 6. The cyclone type dirt separator according to claim 1, wherein said recessed portion is substantially in a shape of a cylinder with a bottom closed.
 7. The cyclone type dirt separator according to claim 1, wherein a diameter of an opening of said recessed portion is approximately ½ to ⅓ of a diameter in the vicinity of a center of said dirt collection chamber.
 8. An electric vacuum cleaner comprising: a cleaner main body provided with an electrically driven air blower; a suction tube with one end thereof connected to a vacuum suction port of said cleaner main body; a suction fitting attached to a tip end of said suction tube; and a cyclone type dirt separator which is provided at an intermediate point of said suction tube, said cyclone type dirt separator causing suction air that contains dirt and is sucked in through a suction fitting to undergo a spiral flow, separating dirt from said air, and causing separated dirt to drop into a substantially tubular dirt collection chamber so that the dirt is collected in said dirt collection chamber; wherein said dirt collection chamber is provided with a recessed portion that is formed in the vicinity of an inside bottom center of said dirt collection chamber and recessed downward. 